This invention relates to a crystallizer comprising an elongated container adapted to hold a crystallizable liquid and provided with cooling elements, and means for causing the crystallizable liquid and the cooling elements to move relative to one another. In particular, the invention relates to a crystallizer for effecting a crystallization of sugar from a supersaturated sugar juice.
In the production of crystalline sugar from sugar juice, the latter is introduced into a boiler in which it is evaporated so as to form a so-called massecuite consisting of supersaturated sugar solution and crystal seeds. The massecuite thus formed is then transferred to a crystallizer comprising cooling elements. During cooling in such a crystallizer, the massecuite is subjected to a movement relative to the cooling elements so as to facilitate the transfer of heat from the massecuite to the cooling elements.
A prior art crystallizer of the above-mentioned type comprises a trough provided with a stirrer having disc-shaped cooling plates connected with means for continuously passing brine through the cooling plates.
Another prior art crystallizer comprises a drum which is rotatable about a horizontal axis, and a plurality of stationary cooling pipes extending through the drum and being fixed to stationary end plates of the drum.
These prior art crystallizers are not fully satisfactory because high forces and a heavy construction are required to generate a satisfactory movement of the massecuite relative to the cooling elements. Therefore, both the initial costs and the operational costs of such crystallizers are high.
The object of the invention is to provide a crystallizer wherein the movement of the liquid to be crystallized relative to the cooling elements is effected in a simple and inexpensive manner.